Automotive continuous conveyor of an articulated type

ABSTRACT

The invention relates to a mobile conveyor wherein an endless conveyor means is mounted on a vertically telescopic framework so that the conveyor means may be raised or lowered to different heights. Further, the conveyor means is itself rotatable about a vertical axis. Respective sections of the conveyor means are articulated to each other whereby they may assume a mutually coplanar orientation when in use, or a compact folded orientation when being transported.

United States Patent AUTOMOTIVE CONTINUOUS CONVEYOR OF AN ARTICULATED TYPE 5 Claims, 12 Drawing Figs.

Primary Examiner-Richard E, Aegerter AltorneyStevens, Davis, Miller & Mosher ABSTRACT: The invention relates to a mobile conveyor wherein an endless conveyor means is mounted on a vertically telescopic framework so that the conveyor means may be raised or lowered to different heights. Further, the conveyor means is itself rotatable about a vertical axis. Respective sections of the conveyor means are articulated to each other whereby they may'assume a mutually coplanar orientation when in use, or a compact folded orientation when being US. Cl 198/233, 198/115, 198/126 Int. Cl ..B65g 21/12, B65g41/O0 Field of Search 198/233, 2l3, I15, 126, 117, I21, I24, 88,87;214/5.2,

83.26 transported.

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SHEET 5 BF 6 H 55. 72 5 l P5 40 4/ 42 25 54 LIONELLO ROSSI INVENTOR ATTO NEYS AUTOMOTIVE CONTINUOUS CONVEYOR-OF AN ARTICULATED TYPE The invention relates to a continuous conveyor device including an endless conveyor means and mounted on a wheeled frame, said conveyor device being associated with. a motor or engine which may drive alternately either the endless conveyor means and the control devices associated therewith, or the same conveyor machine which has to act asa self-moving machine.

A particular characteristic of the invention consists in the fact that the conveyor device has a plurality of sections which are pivotally connected one to the other and are designed for supporting the endless conveyor means, wherein the conveyor device is adapted for movement from an operative to an inoperative position in which the. said sections are folded, enabling the conveyor device to occupy a little space and to attain a very compact arrangement which does not exceed the clearance gauge compulsory for the vehicles intended to be used for transporting load and for self-moving working machines, which have travel along roads. Said folded sections may be also caused to attain an other inoperative position or stowage positioning which they occupy a minimum space. In this stowage position the machine has a volume comprised within the loading gauge of a truck or a trailer. Therefore, when the machine is in this arrangement, it may be put on a truck or on a trailer for transferring the machine over great distances. In the same way, that is to say, when the mach-inc occupies the minimum space, it can be enclosed in a packing container or the like and in this arrangement it can be shipped or sent by rail.

The known self-moving conveyor devices having endless conveyor means, as a belt or other endless device, are adapted to convey material only until limited distances. Further only few types of them can be positioned so as to occupy a minimum space when they are in their stowage position, but for attaining such a purpose it is necessary to remove the belt or the like and to disassemble the several sections forming the supporting frameof said belt, that must be accomplished, if the conveyor device has to be transferred from a location to another and in the case wherein its length exceeds the value which is prescribed for self-moving the vehicles provided to transport load along roads.

The conveyor device of the invention is characterized by the fact that it comprises a central telescopic turret, the upper section of which is connected with revolving means provided to allow the conveyor device to rotate round a vertical axis and with other means enabling the side arms together with a central section, which form the conveyor frame supporting the conveyor means, to rotate along vertical planes, said articulated arms being arranged one in prosecution of the other, and being each constituted of three sections articulated to each other-about horizontal pivot axis. The sections forming said arms are associated with first driving means adapted'to cause the sections of each arm to perform angular movements with respect to the central part of the conveyor ,device supported by the said turret, and with second driving means provided to work in combination with articulated guiding means and adapted to cause each of the said three sections of each arm to perform angular displacements with respect to the adjacent sections, so that the outer sections are pivoted until they rest one other and/or on the said central section, while the other two intermediatesections are pivoted upright until they rest on each other on the front and back respectively of the machine. At the free end olthe outer sections a return roller is provided to support the conveyor belt and to maintain it under tension along its upper working, while near the central portion of the lower return run ofsaid belt two parallel rollers are pro vided, namely a driving rollerland a tensioning roller which are spaced apart one from the other of an adjustable distance so that, as the belt passes round them, it performs a S-like path which comprises two reversals of the travel direction, that enabling the adjustment of the tension of the belt by varying distance between said two rollers. As compared with theconveyor devices of a known type, the, conveyor device of the in-' vention has the following advantages:

a. It permits the material to be delivered at considerable distances from the machine, as for instance, until about 25 m. By means of automated operations the length of the machine can be quickly reduced so that the machine can have a total length of only 7 to 10 m. and a total height-of aminimum value adapted to comply with the rules of the road traffic code in force in the different countries. In such an arrangement the volume of the machine is comprises in the loading gauge, so that said machine could be mounted on a truck or a trailer, in the case wherein very long distances have to be covered at high speeds, which the self-moving machine of this invention could not reach by self, since even if said; machine is automotive, it can cover only the little distances concerned with its specific employments, and, as all the known working self-moving machines, it can travel only with speeds comprised, in a very small speed range.

b. When the machine is arranged in an other inoperative position, it occupies a space comprised within the clearance gauge of the autovehicles, provided by the road traffic code so that. when the machine is in such an inoperative position it can travel along a road and cover the small transferring distances, now acting as a self-moving vehicle. For .such purposes the machine of the invention is provided with variable-gauge wheels, so that said gauge may be varied from a minimum value of about 2.20 m. for the case wherein the machine must be transported on a truck or trailer or is inserted in a packing container or other suitable boxing means, to a value of 2.50 m. which enables the machine to travel on road, acting as a selfmoving vehicle, until a maximum gauge of about 4 m. to be used as the machine must run on hilly ground, as, for instance on a building yard, that is to say, when it is necessary that the machine has the maximum of stability in order to prevent overturning movements and that can be obtained, as well known, by making its bearing base as wide as possible.

Other objects and advantages of the machine ofthe invention will be apparent upon consideration of the following description of one embodiment ofthe invention, given merely by way of an indicative example and not as limiting the invention and with reference to the accompanying drawings, in which:

FIG. 1 .is a diagrammaticside view of;the machine carried on a trailer drawn by a truck;

FIGS. 2 and 3 are diagrammatic side views of the machine, as it acts as a self-moving vehicle and is descending from the trailer (FIG. 2), and as it is travelling along a road (FIG. 3) respectively;

FIG. 4 is a diagrammatic side view of the machine, wherein one of its two foldable arms supporting the conveyor means projects outward beyond the central section of the conveyor device and is unfolded in its horizontal position, while in broken and dotted lines respectively are illustrated two successive positions of the sections constituting said arm and of the means cooperating therewith during-the unfolding stage while the other arm is already arranged in its-folded position,

FIGS. 5 to 9 are side partial views illustrating different operative-positions of the elevator-conveyor device, the guiding means of which have been removed;

FIG. 10 is a plan partial view of the machine, while by broken and dotted lines are illustrated two different positions of the conveyor device, as it has been ungularly displaced towards one side or the other with respect to the longitudinal vertical center plane X-X ol'lhe base frame olthc machine;

FIG. II is a diagrammatic side view of the machine, in an enlarged scale shown as the conveyor device has been un folded in a horizontal plane, in this FIG. the outer portions of side arms of the conveyor device have been cross sectioned with the vertical planes H-II and XX respectively and the corresponding end portions of said arms -.are removed and shown below the representation of the central part of the; machine;

FIG. 12 is a side view similar to that of FIG. 11, but with the upper portion of the conveyor device longitudinally sectioned along a vertical longitudinal plane in order that the inner path of the conveyor belt may be seen. In this FIG. neither the means supporting the belt nor the devices which concern the belt movement have been shown; in this FIG, as in FIG. 10, the end portions of the arms of the conveyor device, have been broken away and displaced below the representation of the central portion of the machine.

With reference to the drawings will be at first briefly indicated and described the main parts of the machine and their mutual dispositions so as to allow to explain the various performances of the machine so that may be better later understood the features and the operative system of the driving means associated therewith.

The machine has a base frame I mounted on wheels 2 of a variable-gauge type. At one of the sides of the frame 1 is positioned a drivers compartment 3 and a driving apparatus generally marked 4 including all the conventional devices for making the machine automotive and conventional power takeoff means provided to drive the various operative devices of the machine. Provision could be made to have independent engines for the different operations or, optionally, motors could be used which are fed of power sources of different types. On the frame 1 a telescopic collapsible turret is arranged which is formed of a plurality of sections 5, 5, 5", 5"40 and provided to carry and to lift or lower the conveyor device and which is actuated by a hydraulic central jack 6, the upper end of which is integral with the upper section 5" of said turret. This section 5" is in turn connected to a center plane or fifth wheel 7 (FIG. 3) rotarily connected to a cooperating female center plate 7' securely fixed to a frame 8 which supports the central plate 7' securely fixed to a frame 8 which supports the central section 11 of the conveyor device. Said conveyor device also comprises two side arms, generally marked 9 and 10 (FIGS. 5 and 7) and the said central section II articulated to each other by means of hinges 9' and 10 which have horizontal axes, said parts 9, l0 and being set in line with each other in some of the operative positions of the conveyor device, but being folded in the transferring or stowage arrangement of the said machine. The said center plate 7 is caused to rotate by means of a second jack 16, ran or the like (FIGS. 3 and 10) thus enabling the conveyor device to be rotated to the left or the right hand through an angle of about for instance, with respect to the longitudinal vertical center plane X-X of the base frame 1 so as to allow the material to be raised from or lowered towards locations on the sides of the machines, as, for instance, in the case wherein material has to be loaded which is piled up in the middle of the road and has to be delivered to locations beyond the road edges, or vice versa.

The central section 11 carries the conventional running rollers designed for supporting and guiding the belt 14, (which have not been shown), as well as means for driving said belt and which will be described hereinafter. The central section I] is pivotally connected directly at 13 to the rear end of the frame 8, while it is connected to the front end ofit with the interposition of a third jack or a pair of jacks 17, which is pivotally connected at 19 to the frame 8 and at 20 to the section 11. The unit 8, 11 and 17 forms a triangular device, one side of which has a variable length and is constituted by said jacks 17, which enable the section 11 to be rotated around a horizontal axis in such a manner that it passes from its horizontal position shown in FIGS. 1 to 5, 7, 8, l1, 12 to the inclined position shown in FIGS. 6 and 9 or to any other posi tion set at any desired angle with respect to the horizontal plane.

- The side arms 9 and 10 are each constituted of three sections 21, 22 23 and 21, 22', 23' respectively. Return rollers 24 for the conveyor belt 14 are arranged at the outer ends of the sections 21 and 21 (FIGS. 3, 11, 12), said sections being pivotally connected at 25 to the adjacent sections 22 and 22' respectively, which in turn are pivotally connected at 27 to the inner sections 23 and 23' respectively, which are articulated to the central section 11 at the hinges l3 and 20 respectively (FIG. 11).

The folding and unfolding movements of arms 9 and 10 formed by the sections 21, 22, 23 and 21', 22, 23' respectively are performed by the interposition of L-shaped plates 26 and 26' so positioned as to be located at one or both sides of the conveyor frame and which are pivotally connected at 13 and 20 respectively to the frames 8 and 11 and to the frame 11 respectively. In the horizontal position of the frames 8 and 11, the short legs of the members 26 and 26' are horizontal and the longlegs are vertical. Between the lower end of the long leg of the member 26 and an intermediate point of the frame 8 is pivotally connected a fourth jack 30 and between the lower end of the long leg of the member 26 and a point near enough to the hinge 20 of the frame 11 is pivotally connected a fifth jack 31. By the actuation of the jacks 30, 31 and I7 may be performed any angular displacement of the whole conveyor device so that it passes, for instance, from the horizontal position shown in FIG. 11 to the inclined position shown in FIGS. 6 and 9 or vice versa.

Between the ends of the long leg of the L-shaped plates 26 and 26' and a point ofthe sections 23 and 23' near the respective hinges 27 are arranged other jacks 32 and 32' respectively. Each of these jacks could be, of course, substituted by a pair of jacks parallel to each other. Said jacks 32 and 32 which are articulated to the parts 26, 23 and 26 and 23 respectively, are provided to force the arms 9 and 10 of the conveyor device to rotate until they are set at the desired angles with respect one to the other or to the section 11, all the longitudinal vertical center planes of the various sections of the conveyor device being always maintained complanar. An articulated guiding rod system is also provided for each of the arms 9 and 10 adapted to coordinate the movements of the sections and to force them to take the mutual desired angular position. Said system comprises four pairs of rods having different lengths 33, 34, 35, 36, which as references is made to the arm 9, at one of their ends are pivotally connected to a common pivot pin 37, while at the other ends each pair of the longest rods 33 are pivotally connected at 38 to a plate 39 projecting out of the end of the section 21, near the outer end of the section 22; the pair of bars 34 is pivotally connected to the short leg of the L-shaped plate 26; the pair of the bars 35 is pivotally connected to the lower part of the section 23 and the pair of the shortest bars 36 is articulated to the upper part of the section 22, the pivot axes of the bars 35, 36 at the connecting points to the frames 23 and 22 are sufficiently spaced apart from the vertical plane passing through the pivot axle of the hinge 27 so as to allow to generate torques. What has been stated above with respect to the sections 21, 22, 23 can be also said again for the sections 21', 22', 23 of the other arm 10, similar parts being marked by similar references.

The length of the bars 33, 34, 35, 36 as well as the position of their pivot axes and the dimensions projecting plates 39, 39 and those of the legs of the L-shaped plates 26, 26', are determined in such a manner that the two systems of rods are adapted to guide the three sections of both two arms of the conveyor device on each side of it so that they can perform the preestablished angular movements. In particular, if reference is now made to FIGS. (3, 4 and 11), in these FIGS. the operations are illustrated which are performed for causing the conveyor device to pass from the operative horizontal position of FIGS. 11 and 12 to the folded inoperative position of FIG. 3.

For such a purpose must be actuated the jacks 32 and 32'. As, for instance, the plunger of the jack 32 performs its return stroke, sliding into the hydraulic cylinder (FIG. 4), the section 23 tends to move downwards and at the same time to rotate aboutthe pivot axis of the hinge 13. As the section 23 lowers, it draws downwards the section 22, and since this latter is in turn pivotally connected by the hinge 27 to the section 23 and by the bars 36 to the pivot pin 37, as the hinge pivot 27 moves downwards, said section 2 tends to rotate in the direction opposite to that of the section 23, until it attains a vertical position, while said section 22 approaches the section 23 and the pivot point 37 also moves downwards, since it constitutes one of the movable apices of a hinged parallelogram shaped guiding structure, the stationary side of which is constituted by the short leg of the member 26 and the other sides are formed by the bars 34, 35 and by the portion concerned of the section 23 respectively. As a result of said downwards movementgof the pivot pin 37, the rod 33 acts as a stud against the outer end of the ear plate 39 forcing this latter and the section 21, which is integral therewith, to move upwards and, at the same time, to rotate in the same rotary direction as the section 22, that is to say in the clockwise direction, if reference is made to FIGS. 3, 4 and 11. As a consequence, the sections 22, 23 will be positioned upright where the section 22. rests on the section 23, afterwards said sections have respectively turned through an angle of 90 but in opposite directions. On the contrary, the section 21 is pivoted, until it rests on thecentral. section 11 or on the section 21' of the arm if this latter section has already'rotate through an angle of 180 so as to attain its folded arrangement shown in FIG. 3. Operations according to the opposite sequence enables the parts to pass. from the positions of FIG. 3 to those of FIG. 11.

-As stated above, in order to enable the parts concerned to perform the preestablished movements, the collapsible turret must be partially caused to vertically extended and will be then fixed in this position in the case wherein the. machine together with the conveyor device, now in its-folded arrange-- ment (FIGS. 2 and 3) must go on or down a carriage 12 (FIG. 2) or must travel along,a,road.(FlG. 3).

Other different positions of the parts are obtained by actuating one or more of the jacks l6, I7, 30, 31. For instance, in order to vary the angular position of the longitudinal vertical center plane of the conveyor device with respect to the cor responding center plane X-X of the frame. I mounted on wheels 2.the jack l6 must-be actuatedprovided for controlling the rotation of said conveyor device round a vertical axis, and which acts on the female center plane 7' cooperating with the center plate 7'. In order to vary the angular position of the arm 9 with, respect to thesection 11 must be made operative the jack 30 and for varying. the angular position of the arm 10 will be actuated the jack 31.

As it is desired to vary the inclination of the conveyor device, as all its sections are in line, so that its longitudinal axis passes from thehorizontal. operative position to any inclined operative position (FIG. 6) the jack 17 will be actuated.

By actuatingtwo or more of thes aid jacks at thesame time and by moving up and down if required the vcollapsible'turret by means of the jack 6a wide range'of operative'positions of the conveyor device can be obtained, some of whichare'illustrated inthe Figures of the accompanying drawings. Asfar as the conveyor device is concerned, it is to benoted' that the endless conveyor means is preferably a rubber belt or an endless link stripor other suitable means, which is. only dia grammatically shown-in FIGS. 3 and 12.. Said belt l4-has an upper working run guided over andbetweenthe tworeturn rollers 24.:The lower return run of this belt formsat the central zone a S-shaped path. where said belt 14 passes round a driving roller 40-and.then round atensioning roller 41 so that along said path two reversalsof the advancing direction of the belt l4 take place. The tensioning roller 4l is carried by adjustable supporting means, as for instance, ascrew device=42 or the like, enabling to adjustthe tension of the conveyor belt 14 by duly varying the distance between the stationary driving roller 40 and the movable tensioning roller41 The driving roller. 40-is preferably driven by an oleodynamic" transmission. Provision could also be made of a pumping oleodynamic. apparatus (not; shown), adapted to operate the different jacks which is controlled from'a centralized control board and includes suitable nozzles, pipes and valves or the like. In the same way-the. motionmay be transmitted to the driving wheels2 by means of two oleodynamic motors connected one to the. other, in paralleland which in combination act as a differential system, allowing the gaugeof the-wheels 2 suitable means are maintaining thewheels'2 lifted up away from the ground. i"- I In FIG. 1 the machine is in its stowage position in whichthe wheels 2 are spaced apart from each other according tothe .machine and the outer sections rest onelon the other lengthwise the central section 11 of the conveyor device. In

this arrangement thewheeled machine may by put on a truck or on a trailer 12 (FIGS. land 2) drawn by a tractor 15 or the like or could be inserted in a container or ojther boxing meahs in order tobe shipped. I I

Afterw'ardsthe machine has been transported until or near the place, where it has to be used, the tutret'Sto 5" is caused to sufficiently raise (FIG. 2) so that the parts of the conveyor device which are positioned at the front of said machine are raised enough as to do not prevent the travel and the steerage of the machine, as this latter, acting as a' self-movin'gvehicle, comes down by itself from the trailer 12 or the like. Before the beginning of the travel of the machine towards its use location, it is. necessary to vary the gauge of the wheels 2 until it attains the-normal value provided for a self mo vi ng machine which must travel along common roadways, or saidgauge must be increased until its maximum value (dottedposition of the wheels 2.in FIG 10), if the machine mustrun on auneven ground. As said self-moving machine attains its working place, it will be put in the desired operative position. Forsuch a purpose the turret 5 to 5" is caused to be optionally extendedin such a way to enable the various parts to perforrnthe preestablishedmovements-in order to force the arms 9and 10 to beunfolded (FIGS. 4and 5). Afterwards, by varying the height of the'turret and/or by varying theangular' positions of'the arms 9 and 10 with respect to the central section 11 and/or by varyingthe angle of longitudinal axes of said central section 11 with respect of 'thehorizontal plane, while always keeping the longitudinalaxes of the sections 9, 10, II in a'same plane and/or by rotarily moving the conveyor device about a'vertical axis by means of the rotary slidingdevice 7,7 driveri'by thejack 16 with respect of the-frame 1, any workingposition may be attainedadapted to convey the material alonga horizontal or inclined paths.

1 claim: I l

1. A continuous conveyor device of an articulated type supportinga common endless conveyor meansand carried on a frame mounted on wheels of a variable-gauge-and provided witha motor and other means to make themachine automotive, wherein said machine comprises a central telescopic turret, the upper part of which is connected= to the conveyor device through means adapted for rotation-'of'said conveyor device round a vertical axis, said conveyor devicecomprising a centralsection'supported by the said'rotary'ine'ans with the interposition of an articulated frame "two side arms pivotally connectedat the ends of the said entral secti'onand' having coplanar longitudinalaxes, each of satd 'two'arms being constituted of three sections articulated td-each other about horizontal-pivot axes, first operating meansheing-associated are pivotedinto their upright positions and=-rest= one on'the other facing the back/and the front of the'ma chine*,"or'to penformthe same movementsin an opposite sequence,- at thefree end of the outer sections of both arms a return" roller being'arranged to support the upper working run of the endless conveyor means, while near the central part of the return run of said endless conveyor means a driving roller and a tensioning roller are arranged having parallel axes and spaced apart from one another of an adjustable distance and round which passes the endless conveyor means travelling along a S-like path ineluding two reversals of the advancing direction of said endless conveyor means, thus enabling to adjust the tension of said endless means by duly varying the mutual distance of said two rollers.

2. A continuous conveyor device according to claim 1 wherein the tensioning roller is carried by movable supporting members enabling to moving said tensioning roller to and from the driving roller so that the increase and decrease of the tension of the endless conveyor means depends upon the adjustment of the distance between the movable tensioning roller and the stationary driving roller.

3. A continuous conveyor device according to claim 1, whereinthe telescopic central turret is constituted by a plurality of collapsible sections, the lowermost of which is fixed to the wheels frame of the machine and the uppermost one is connectedto the central section of the conveyor device through means provided for rotation of said conveyor device round a vertical axis and through an articulated frame provided for rotation of said central section about a horizontal axis, said rotary connecting means as a center plate associated with a female center plate and said articulated frame being actuated respectively by operative devices as jacks or the other suitable device having a variable length.

4. A continuous conveyor device according to claim 1, wherein a system of pairs of guiding rods are associated to each of the said articulated arms and is provided to coordinate the movements of the sections forming each arm, said pairs of rods being pivotally connected at one end to a common pin and at the other end to the various sections of the same arm and to the central section of the conveyor through a L-shaped plates which are connected to the ends of the central section respectively each of said L'shaped plates including a long leg projecting downwards, said long leg of each of the L-shaped plates, supporting an operating device having a variable length which is pivotally connected to said leg and to the central section at a point near the adjacent end of it, while another operative device having a variable length is pivotally connected between said leg and a point of the end of said arm adjacent the central section of the conveyor device, said second operative device controlling the folding and unfolding operations of said arm, in cooperation with the said articulated guiding rod system.

5. A continuous conveyor device according to claim 1, wherein the length of the central section of the conveyor device is substantially equal to that of each of the outer sections of the articulated arms and is substantially not longer than the length of the wheeled frame, while the length of each of the two intermediate sections of both arms is substantially equal to the amount of the height of the turret in its collapsed position and of that of the supporting wheeled frame in such a way that, as the machine is in its stowage position, the pairs of upright positioned sections of the conveyor device facing the back and the front of the machine nearly approach the ground. 

1. A continuous conveyor device of an articulated type supporting a common endless conveyor means and carried on a frame mounted on wheels of a variable gauge and provided with a motor and other means to make the machine automotive, wherein said machine comprises a central telescopic turret, the upper part of which is connected to the conveyor device through means adapted for rotation of said conveyor device round a vertical axis, said conveyor device comprising a central section supported by the said rotary means with the interposition of an articulated frame and two side arms pivotally connected at the ends of the said central section and having coplanar longitudinal axes, each of said two arms being constituted of three sections articulated to each other about horizontal pivot axes, first operating means being associated with said sections forming the said articulated arms, which are adapted to cause said sections, when aligned, to perform angular movements with respect to the central section of the conveyor device, and second operating means which act in combination with articulated guiding means being provided to force each of the said sections to rotate with respect to the adjacent section of both arms until each outer section of said arms is pivoted in a horizontal position and rest on the central section, while the other two intermediate sections of each arm are pivoted into their upright positions and rest one on the other facing the back/and the front of the machine, or to perform the same movements in an opposite sequence, at the free end of the outer sections of both arms a return roller being arranged to support the upper working run of the endless conveyor means, while near the central part of the return run of said endless conveyor means a driving roller and a tensioning roller are arranged having parallel axes and spaced apart from one another of an adjustable distance and round which passes the endless conveyor means travelling along a S-like path including two reversals of the advancing direction of said endless conveyor means, thus enabling to adjust the tension of said endless means by duly varying the mutual distance of said two rollers.
 2. A continuous conveyor device according to claim 1 wherein the tensioning roller is carried by movable supporting members enabling to moving said tensioning roller to and from the driving roller so that the increase and decrease of the tension of the endless conveyor means depends upon the adjustment of the distance between the movable tensioning roller and the stationary driving roller.
 3. A continuous conveyor device according to claim 1, wherein the telescopic central turret is constituted by a plurality of collapsible sections, the lowermost of which is fixed to the wheels frame of the machine and the uppermost one is connected to the central section of the conveyor device through means provided for rotation of said conveyor device round a vertical axis and through an articulated frame provided for rotation of said central section about a horizontal axis, said rotary connecting means as a center plate associated with a female center plate and said articulated frame being actuated respectively by operative devices as jacks or the other suitable device having a variable length.
 4. A continuous conveyor device according to claim 1, wherein a system of pairs of guiding rods are associated to each of the said articulated arms and is provided to coordinate the movements of the sections forming each arm, said pairs of rods being pivotally connected at one end to a common pin and at the other end to the various sections of the same arm and to the central section of the conveyor through a L-shaped plates which are connected to the ends of the central section respectively each of said L-shaped plates including a long leg projecting downwards, said long leg of each of the L-shaped plates, supporting an operating device having a variable length which is pivotally connected to said leg and to the central section at a point near the adjacent end of it, while another operative device having a variable length is pivotally connected between said leg and a point of the end of said arm adjacent the central section of the conveyor device, said second operative device controlling the folding and unfolding operations of said arm, in cooperation with the said articulated guiding rod system.
 5. A continuous conveyor device according to claim 1, wherein the length of the central section of the conveyor device is substantially equal to that of each of the outer sections of the articulated arms and is substantially not longer than the length of the wheeled frame, while the length of each of the two intermediate sections of both arms is substantially equal to the amount of the height of the turret in its collapsed position and of that of the supporting wheeled frame in such a way that, as the machine is in its stowage position, the pairs of upright positioned sections of the conveyor device facing the back and the front of the machine nearly approach the ground. 